And it's not the only one we found collecting dust, because something went wrong 14 of the 16 times they tried to use it last year.

[From Batman movie:

Robin: Holy nightmare!]

In March it was the AC. Think in six months they could've fixed that? After all, the van wasn't being used to process a single drunk driving suspect.

Look at September's maintenance report. Still hot air blowing. The temperature in the van is crucial to proving who's drunk and who's not.

"The breath instruments have to be maintained at certain temperature, so if it's not cooling properly, you can't use the instruments," Murphy said.

In six months. One BAT van processed only two suspects. Turns out electrical problems had interfered with the Intoxilyzer machine.

[From Batman movie:

Batman: It could be compromising.

Robin: Of course. ]

In May, an email detailed electrical problems in most of the BAT van fleet, quoting, "This is having a very negative effect on the four $6,000 Intox instruments ... and the overall effectiveness of the BAT vans."

The lieutenant was worried about having to, quote, "explain what these problems can do to pending court cases."

"The lieutenant may think there's a problem, but I don't see that there's a problem," Driskell said.

And the DA's office has never been told of any of the maintenance problems we've uncovered.

"It is so sloppy and it's an embarrassment. HPD has been cutting corners on science," Murphy said.

"It's not that we're trying to hide it, but I don't see a need in telling them that. If they wanna know that, we'd be glad to share that information," Driskell said.

"Have they ever asked?" we asked him.

"No," he replied.

"They took an inaccurate device and made it even more unreliable," Murphy said.

[From Batman movie:

Robin: Holy Merlin the Magician! We're in for a shock.]

HPD emails show some of the BAT van personnel have actually failed the test to do the drunk test. Even today, some members of Houston's DWI task force haven't even taken the test.

"We're gonna get out there and we're gonna find some of these drunks before they get into crashes," said HPD Assistant Chief Brian Lumpkin of a new drunk driving crackdown initiative.

HPD knew this story was coming when they announced their big DWI crackdown this month. They now promise these two-year-old barely used BAT vans will be out every single weekend, four of them. But you paid for six.

"I think if you come back and do this story next year, you'll see that the vans are much more utilized," Driskell said.

We used Batman and Robin to help illustrate the trouble with the BAT vans, but make no mistake, when taxpayers buy crime fighting weapons, they want to see them used.